Title: Minimum real time bang-bang fuzzy control system

Authors: Farrukh Nagi

Addresses: Department of Mechanical Engineering, University Tenaga Nasional, Malaysia

Abstract: Minimum-time control is desired for non-linear spacecraft–satellite attitude systems to save on board thruster fuel. The regulatory time depends on the initial attitude of the satellite. Bang-bang control of satellite attitude can be accomplished with Fuzzy Logic Controller (FLC) using Largest of Maxima (LOM) defuzzification technique. In case of fuzzy controller, earlier studies show that minimum response time depends on span of the fuzzy controller membership functions. This paper shows how the non-linear relation between the initial attitude of satellite and spans of the fuzzy controller membership functions are optimised to achieve minimum response time by using Nelder–Mead simplex search method. A practical demonstration of fuzzy bang-bang control is demonstrated here by controlling angular position of a single-axis attitude application. The pneumatic rotary actuator is controlled in real time using Matlab-simulink xPC target environment.

Keywords: bang-bang control; fuzzy control; attitude; largest of maxima; on-board thruster fuel; pneumatic rotary actuators; defuzzification; optimisation; minimum-time control; spacecraft attitude systems; satellite attitude systems; fuzzy logic controllers; FLC.

DOI: 10.1504/IJAAC.2009.023072

International Journal of Automation and Control, 2009 Vol.3 No.1, pp.74 - 90

Received: 30 Jan 2008
Accepted: 26 May 2008

Published online: 08 Feb 2009 *

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